Explanation: As the Sun sets, the Earth's
shadow rises up from the east.
The subtle beauty of
this
daily apparition is often overlooked
in favor of the brighter, more colorful
western horizon.
But while gazing toward a nearly full rising Moon on August 9,
astronomer Steve Mandel admired the shadow rise from his driveway
near Soquel, California, USA.
His view looks east from the northern tip of Monterey Bay toward
Fremont Peak, the highest point in the small mountain range on
the horizon.
The
Earth's rising shadow is cast through the
dense atmosphere and is seen in his picture as the dark blue band
along the horizon, bounded above by a pinkish purple glow or
antitwilight arch.
Also known as the Belt of Venus,
the arch's lovely color is due
to backscattering of
reddened
light from the setting Sun.